Fake owls are just that – fake. You may think that by putting up a fake owl, you will scare away gulls, crows, and other bothersome birds. And that fake owl may work, but only for a few days. After that, the birds will simply get used to the unmoving statue and think of it as part of the landscape.
Window Guards need not be Hawks. Windows are a danger to birds. Since they are see-through, birds try to fly right through them, and can be injured or killed. Also, a bird may see its reflection, and think it sees another bird, so it will fight with the window, bashing it self against the window to get to the other bird. A way to protect birds in both these cases is to break up the window into segments. Hawk decals are popular, but it is not the hawk that is important. Rather, it is the breaking up of the clear area, so it doesn’t look like open space. You can do this with curtains, a potted plant, or by putting some tape across the windows.
Bird Migration is Variable. Some birds make complete migrations. They fly north for breeding, and then winter well to the south. Other birds nest, breed, and winter all in the same place. Some birds nest and breed in the north, but then only migrate some years. There are frequent “irruptions” – that is, where birds show up in great numbers in unexpected places at unexpected times. And there are partial migrations, where some of the birds migrate but others of the same species don’t.